The use of various indwelling catheters, especially feeding devices, is well known in the medical art. Feeding tubes may be left in place within the body for a considerable period of time, often up to a year. This is possible due to the use of recent advancements in biocompatible materials, especially silicone indwelling devices which permit long term placement of a device without body rejection or tissue reaction. Medical grade silicone devices are routinely used in gastrostomy feeding devices as well as other types of devices such as wound drains and infusion catheters. The silicone material has many biocompatibility advantages including the ability to remain soft and flexible for long periods of time within the body.
Feeding devices and catheters made from silicone are molded, extruded, and assembled such that the silicone material is very smooth and the surface finish has a very low coefficient of friction. The surface of the silicone catheter becomes very slippery especially when it is in contact with body fluids. As a result, these devices have displayed a tendency to migrate after they have been implanted. To prevent inward migration, designers and manufacturers have added external retention devices to their products. Silicone retention discs are manufactured in various sizes to stabilize catheters and are produced by such companies as Wilson-Cook. Low profile gastrostomy ports of fixed length are also are available in various sizes and lengths with integrally molded bolsters incorporated therein to prevent tube migration.
Retention discs may easily slide on the tubular shaft of the catheter allowing the migration of the catheter into the body. If the catheter slips a sufficient distance this may allow an inner balloon to cause an obstruction or require adjustment of the device. Pull ties have been added to these discs to prevent disc slippage, however, the disc can still fail even with the pull tie in place, due to the smooth slippery outer surface of the catheter and the smooth inner surface of the molded retention disc.
Gastrostomy devices commonly are supplied in various fixed lengths to accommodate differing lengths of stoma tract. Gauderer U.S. Pat. No. 4,803,438, and Russo U.S. Pat. No. 4,944,732, disclose examples of low profile devices that are supplied in various fixed lengths for this purpose. Patients, however, cannot be fitted with a fixed length device when the correct length is not available. Therefore, a large inventory of these devices in a variety of fixed lengths and sizes needs to be maintained at a considerable added expense. This type of device also requires additional equipment to measure the lengths of patients' stoma tracts to determine appropriate sizing for placement. These disadvantages have limited the usefulness for such low profile devices.